p-Fluorophenethylamine → 5-(4-{[2-(4-Fluorophenyl)ethylamino]methyl}-2-methylphenoxy)pyrazine-2-carboxamide

Participants

Reaction Steps

Place 5-(4-formyl-2-methylphenoxy)pyrazine-2-carboxamide (Example 404, part D) (0.600 g, 2.33 mmol), 2-(4-fluorophenyl)ethylamine (0.325 g, 2.33 mmol) and 3 {acute over (Å)} molecular sieves in a vial. Add methanol (11.7 mL), cap and stir overnight. Add NaBH4 (0.088 g, 2.33 mmol) and stir until the gasses stop evolving. Load the reaction mixture directly onto a 25 g ISCO® pre-load column. Dry the column in a vacuum oven at room temperature. Purify by eluting through a 40 g ISCO® column with 5% to 20% (2.0 M NH3 in methanol) in ethyl acetate. Concentrate the fraction containing the product, then take it up in EtOAc (100 mL). Wash the organic solution with 1.0 N NaOH (2×25 mL), dry it over Na2SO4 and concentrate it to give the title compound (0.478 g, 54.0%): TOF MS ES+ 381.2 (M+H)+, HRMS calcd for C21H22N4O2F 381.1727 (M+H)+, found 381.1729, time 0.39 min; HPLC [YMC-Pro pack C-18 (150×4.6 mm, S-5 microm), 0.05% TFA/acetonitrile in 0.05% TFA/water at 1.0 mL/min, 10-20% over 5 min, 20-95% over 18], tR=11.3 min, 97.8% purity.

Provenance & Evidence